1. Field of the Invention
The present invention relates to extraction solvents, and particularly to aqueous two phase systems that contain partly urethanized PVA (polyvinyl alcohol) and a copolymer formed from the monomers diallylammonioethanoate, dodecyldiallylammonium chloride and sulphur dioxide that can be used for the extraction of biomolecules of interest.
2. Description of the Related Art
Aqueous solutions of appropriate concentrations of two polymers, a polymer and a salt, or other alternative components, when combined above or below a certain critical temperature, lead to the construction of biphasic systems known as aqueous two-phase systems (ATPS). ATPS, having the advantage to be readily scaled-up, are efficient, inexpensive, environmentally friendly and biocompatible liquid-liquid extraction systems that have been widely used to separate and purify a variety of industrially important biomolecules. Unequal distribution of biomolecules, such as amino acids and proteins, in ATPS leads to the efficient separation and purification of the biomolecules in downstream processes of biotechnology.
The most commonly used ATPS are based on poly(ethylene glycol) (PEG) and dextran. In some cases, the polymers have been modified with hydrophobic groups and biospecific ligands for the affinity partitioning of biomolecules. The efficient use of a hydrophobically modified acrylamide-styrene copolymer-PEG aqueous two-phase system in the separation of bovine serum albumin has been demonstrated.
In an effort to develop suitable ATPS, the effect of pH and salt concentration on the coexistence curves of a system containing the pH-responsive copolymer poly(diallylammonioethanoate-alt-sulfur dioxide) and polyethylene glycol has been reported. The system has been successfully employed in the study of protein partitioning; extremely high partitioning levels (partition coefficient of 0.004) and very high separation ratios of bovine serum albumin and cytochrome c (up to 48) were recorded. Hydrophobicity is a key feature that determines the partitioning of proteins in ATPS.
Thus, aqueous two-phase systems solving the aforementioned problems is desired.